K2S2O8-Mediated Arylmethylation of Indoles with Tertiary Amines via sp3C-H Oxidation in Water

A transition-metal- and catalyst-free, highly efficient synthesis of 3-arylmethylindoles has been achieved using tertiary amines as both methylene (-CH (2) -) transfer and arylmethylation agents and K (2) S (2) O (8) as a convenient oxidant. The key feature of this protocol is the utilisation of K (2) S (2) O (8) as an inexpensive and easy to handle radical surrogate that can effectively promote the reaction, leading to the formation of C(sp (2) )-C(sp (3) )-C(sp (2) ) bonds via sp (3) C-H bond oxidation in water at room temperature in a one-pot procedure.